GHD can be used as the basis of many more predictions, which can immediately be written for soliton gases. As an example, the presence of external potentials coupling to any conserved density in GHD was described in [1]}, and suggests, for instance, that the kinetic soliton gas equation for evolution under
\(u_t + (\alpha (x) (3 u^2 + u_{xx}))_x = 0\) 
